Apparatus for producing ultraviolet radiation

ABSTRACT

Apparatus for treatment of humans with ultraviolet rays has one or more mercury lamps, Xenon lamps or other radiation sources and associated reflectors which establish a high-density radiation field in close proximity to the exit opening or openings. The radiation is filtered so that the body of a person located in the region of the high-density field is exposed only to rays in the range of 315 to 400 nanometers. The heat energy output of the radiation source or sources is sufficiently low to enable a person to stand long periods of uninterrupted exposure to radiation in the range of 315 to 400 nm so that a tanning effect can be achieved as a result of a single continuous exposure for a requisite interval of time. Alternatively, the apparatus is equipped with suitable heat absorbing and intercepting means, especially if the radiation source or sources are high-pressure mercury lamps or Xenon lamps. The apparatus can constitute a table model, a floor model, a ceiling model, a wall model or a combination of these.

CROSS-REFERENCE TO RELATED CASES

This is a division of my copending application Ser. No. 885,123 filedMar. 10, 1978, now U.S. Pat. No. 4,196,354 granted Apr. 1, 1980. Theapplication Ser. No. 885,123 is a division of Ser. No. 716,253 filedAug. 20, 1976, now U.S. Pat. No. 4,095,113 granted June 13, 1978.

BACKGROUND OF THE INVENTION

The present invention relates to radiation producing apparatus ingeneral, and more particularly to improvements in apparatus which can beused for tanning of human skin and/or for therapeutical purposes. Stillmore particularly, the invention relates to apparatus (popularly knownas sunlamps) which are designed to produce and orient infrared and/orultraviolet radiation. Such apparatus comprise one or more radiationsources (e.g., ultraviolet lamps), one or more reflectors and means(including or constituting the reflector or reflectors) which definesone or more exit openings for radiation.

Sunlamps are often classified according to the dimensions of theradiation field. Thus, a table model is normally designed for directingradiation against selected areas (especially the face and the upper partof the torso) of the human body, and a floor, wall or ceiling model isnormally (but not invariably) designed to direct radiation against theentire body. Sunlamps of the type capable of producing radiation fieldswhich are large enough to effect simultaneous tanning of all parts of ahuman body are sometimes called solaria. As a rule, a person who isabout to acquire artificial tan by using a table model must bepositioned at a distance of 60 to 100 centimeters from the exit openingof the sunlamp. In a solarium, whose radiation source or sources arenormally installed at a level above a bunk, couch, cot or bed, theprescribed distance from the exit opening is in the range of 120 to 200centimeters. A table model frequently comprises a single radiationsource, and a solarium comprises several (often three) radiationsources, especially in the form of high-pressure discharge lamps forultraviolet radiation. The output of radiation sources for table modelsis 100 to 150 watts. 150 to 200 watts for relatively small solaria(normally for use in private homes), and 350 to 500 watts for use ingiant solaria.

A sunlamp is used primarily to produce a sun-tanning effect. However,before a conventional lamp produces a discernible tanning effect,ultraviolet radiation causes many other (mostly undesirable) biologicaleffects, such as reddening of the skin (sunburn) which entails flakingand hardening of the skin. Since the minimum dosage of ultravioletradiation which produces sunburn is reached within minutes (especiallyif the density of the radiation field in the region of exposed skin ishigh), i.e., well before the skin begins to exhibit even a slight traceof tanning, the exposure of skin to ultraviolet radiation must berepeated again and again whereby the duration of exposure normallyincreases from treatment to treatment. However, even the just describedmode of using a sunlamp cannot produce a deep tan such as is acquired byprolonged exposure to sun rays.

SUMMARY OF THE INVENTION

An object of the invention is to provide a novel and improved apparatusfor producing ultraviolet radiation, expecially a sunlamp which isconstructed and assembled in such a way that a person desiring toacquire a pronounced tan must undergo a relatively small number oftreatments or a single treatment.

Another object of the invention is to provide an apparatus which iscapable of producing a pronounced tan without sunburn and/or otherundesirable effects which are unavoidable consequences of theutilization of conventional sunlamps.

A further object of the invention is to provide an apparatus which canbe used in commercial or other establishments or in homes, which is ofeye-pleasing appearance, and which can be used by fair-skinned personswithout any danger of sunburn or other unpleasant effects which developas a result of exposure to radiation produced by conventional sunlamps.

An additional object of the invention is to provide a novel assembly ofradiation source or sources and one or more reflectors for use in theimproved sunlamp.

An ancillary object of the invention is to provide an apparatus whoseheat energy output is sufficiently low to permit longlasting exposure ofhuman skin to ultraviolet radiation without any discomfort to the personor persons using the apparatus.

Another object of the invention is to provide novel and improvedradiation filters for use in the above outlined apparatus.

An additional object of the invention is to provide an apparatus whichcan be designed as a table model, a floor model, a ceiling model or awall model and which can be used by a single person or simultaneously bytwo or more persons.

A further object of the invention is to provide an apparatus whose exitopening or openings for ultraviolet radiation can be placed intoimmediate or close proximity to the skin without any danger of sunburnor other undesirable biological effects.

Another object of the invention is to provide novel and improved meansfor supporting one or more apparatus of the above outlined character.

One feature of the invention resides in the provision of an apparatusfor producing ultraviolet radiation, particularly a sunlamp, whichcomprises at least one high- or low-pressure mercury vapor lamp oranother suitable source of ultraviolet radiation, reflector meansassociated with the source or sources to define therewith at least oneexit opening for ultraviolet radiation as well as to establish ahigh-density radiation field of predetermined area in or close to theregion of the exit opening or openings, and suitable filter means forintercepting at least the major percentage of predetermined wavelengthbands of ultraviolet radiation ahead of the field so that the fieldconsists essentially of the remaining wavelength band of ultravioletradiation, preferably between 315 and 400 nanometers.

If the source or sources are such that the emission of ultravioletradiation is accompanied by the generation of substantial quantities ofheat energy, the apparatus further comprises heat absorbing orintercepting means which is interposed between the source or sources andthe field to maintain the temperature of the region of the field withina range which is below the range of discomfort to the person or personswhose skin or skins are exposed to radiation. Alternatively, the sourceor sources may include one or more lamps whose heat energy output issufficiently low to insure that the temperature in the region of theradiation field is within the aforementioned range (i.e., within a rangebelow the range of discomfort to the person or persons whose skin orskins are exposed to radiation).

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved apparatus itself, however, both as to its construction and itsmode of operation, together with additional features and advantagesthereof, will be best understood upon perusal of the following detaileddescription of certain specific embodiments with reference to theaccompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a horizontal sectional view of an apparatus with a battery often upright radiation sources which embodies one form of the invention;

FIG. 2 is an enlarged view of a detail in FIG. 1, showing one of theradiation sources and the associated reflector;

FIG. 3 is a diagram whose curves denote the sensitivity of human skin tosunburn and the tanning effect upon human skin in different bands ofultraviolet radiation;

FIG. 4 is a similar diagram showing the emission of radiation in theultraviolet, visible and infrared ranges by resorting to different typesof radiation sources;

FIG. 5 is a schematic partly side elevational and partly verticalsectional view of a second apparatus;

FIG. 6 is a schematic side elevational view of a third apparatus;

FIG. 7 is a perspective view of a fourth apparatus;

FIG. 8 is a schematic perspective view of certain details in theapparatus of FIG. 7;

FIG. 9 is a perspective view of a fifth apparatus;

FIG. 10 is a perspective view of a sixth apparatus;

FIG. 11 is a perspective view of a seventh apparatus;

FIG. 12 is a plan view of the apparatus of FIG. 11, with the roofremoved;

FIG. 13 is a perspective view of a portion of an eighth apparatus;

FIG. 14 is a schematic end elevational view of a ninth apparatus;

FIG. 15 is a schematic partly end elevational and partly verticalsectional view of a tenth apparatus with two units located one above theother;

FIG. 16 is a perspective view of an eleventh apparatus which resembles abarrel; and

FIG. 17 is a schematic sectional view of a twelfth apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows an apparatus which comprises a housing 1 the front side ofwhich has an exit opening or window 2 for ultraviolet radiation. Thehousing 1 contains a battery of ten parallel upright rod-shapedradiation sources 3 (hereinafter called sources) whose axes are locatedin an arcuate plane a. Each source 3 is assumed to be a low-pressuremercury lamp having a length of 150 centimeters and an output of 65 to120 watts, preferably closer to 120 watts. Each source 3 is associatedwith a trough-shaped reflector 4 of the type shown in FIG. 2 (or withone of other types of reflectors disclosed in my copending applicationSer. No. 716,254 filed Aug. 20, 1976 and entitled "Reflector for use insunlamps or the like").

The battery of sources 3 and reflectors 4 is flanked by two infraredheaters 5 which are optional. These heaters can be used alternativelywith the sources 3. Each heater 5 may comprise an electrically heatedrod consisting of silicon carbide.

The housing 1 further contains auxiliary equipment 6 (e.g., timers andchokes) and controls 7 including a starter knob 8 which is accessible atthe exposed side of the left-hand side panel of the housing. Each source3 comprises a tubular (preferably cylindrical) envelope 3a (see FIG. 2)made of glass which constitutes a filter by intercepting predeterminedwavelength bands of ultraviolet radiation while permitting the remainingband to reach the window 2. The envelopes intercept all or nearly allradiation within the so-called UVC range ("far" region) of 200 to 280 nm(nanometers) and within the so-called UVB range ("Dorno" region) of 280to 315 nm, but do not intercept radiation within the so-called UVA range("near" region) of 315 to 400 nm.

The window 2 contains a pane 9 and the housing 1 further comprises aframe 10 for the window 2 as well as doors 11 which are pivotablebetween the illustrated (open) positions in which the window 2 isexposed and closed positions in which they conceal the window. It willbe noted that the housing 2 contains all essential components of theapparatus; this housing may resemble a cabinet, e.g., a cabinetresembling the housing of a television receiver, which is ofeye-pleasing appearance not only when in use but also when the doors 11are closed. The doors 11 and/or other parts of the housing 1 can beprovided with suitable ornamentation to further enhance the appearanceof the apparatus.

The distance b between neighboring sources 3 in the housing 1 may equalor approximate 70 percent of the diameter c of a source. Thus, thedistance between the central symmetry planes 12 of neighboring sources 3equals b+c. The symmetry planes 12 are normal to the plane a. Thesymmetry planes 12a and 12b of the two outermost sources 3 make an angleof less than 80 degrees, for example, 45 degrees.

The assembly of sources 3 and reflectors 4 establishes a high-densityradiation field 13 in front of the pane 9. The distance d between thewindow 2 and the field 13 is assumed to equal or approximate 10centimeters. The width e of the field 13 is assumed to be 70 centimetersand its height (as considered at right angles to the plane of FIG. 1) is150 centimeters (i.e., it matches the length of a rod-shaped source 3).The apparatus of FIG. 1 produces a high-density field 13 because thedistance between the sources 3 and the field is very small, because ofthe substantial number of sources 3, because of the aforementionedoutput (65 to 120 watts) of the sources and also due to the fact thatthe axes of the sources 3 are located in a common plane whose concaveside faces the window 2. The high density of the field 13 is furtherattributable to the improved design of the reflectors 4 which aredisclosed and claimed in the aforementioned copending application Ser.No. 716,254. The density of the field 13 may equal or approximate 12mw/cm². As a rule, the density decreases in a direction from the centerof the window 2 toward the doors 11 (i.e., toward the vertical marginalportions of the field); however, the minimum density in the region ofsuch marginal portions is still much higher than 4 mw/cm².

It is clear that the axes of sources 3 may be placed into a plane whichis exactly parallel to the plane of the pane 9, or that the battery ofsources 3 may be arrayed in another formation, e.g., the sources mayform a zig-zag array each section of which includes two, three or evenmore parallel sources.

The apparatus of FIG. 1 is not only simple but also very compact andrelatively inexpensive. Its energy requirements are low. For example,the plug of its electric cable (not shown) can be inserted into ahousehold outlet of a circuit which is secured by a 10-ampere fuse.

The number of sources 3 in the apparatus of FIG. 1 can be reduced belowor increased above ten. For example, the number of sources may beanywhere between five and twenty, preferably ten to twelve. TheUVA-radiation output of each source 3 is preferably at least 5 watts permeter of the source. The heat energy output of low-pressure mercurylamps is so low that an entire battery of such lamps can be used in theapparatus of FIG. 1 without causing any discomfort to a person standingvery close to the window 2. Since the UVA-radiation output of alow-pressure mercury lamp is very low, such lamps are preferably placedvery close to each other and each reflector 4 preferably surrounds therespective lamp from three sides to insure that a very high percentageof UVA radiation is caused to form a high-density field at or close tothe window 2. The length and width of the field 13 can be selected atwill, i.e., by the simple expedient of selecting a requisite number ofradiation sources having a desired length.

Since the tanning effect is produced more rapidly if the UVA-radiationoutput of the sources is relatively high, it is desirable to selectlow-pressure mercury lamps with a relatively high output (at least 8watts per meter) of UVA radiation. Many recent types of such lamps havean output of at least 10 w/m.

If the apparatus is to be used for simultaneous exposure of the entirebody to radiation in the optimum band of ultraviolet light, the lengthof sources 3 preferably exceeds 100 centimeters and most preferably 150centimeters. Such sources are economical because the necessary firingpotential is relatively low and the apparatus must embody a relativelysimple and inexpensive auxiliary equipment. The optimum length ofsources which are used in a solarium (for simultaneous exposure of allparts of the body of an adult to ultraviolet radiation) is approximately180 centimeters.

The overall output of conventional rod-shaped radiation sources having alength of 150 centimeters and being capable of furnishing satisfactoryradiation in the UVA band is at least 100 watts, normally 120 watts. Byappropriate treatment, the overall output of such sources can be reducedto 80 watts without reducing their output in the UVA band of ultravioletradiation.

The selected spectral data (especially as regards the UVA radiationoutput) should not fluctuate during treatment. Since a shift normallytakes place in response to changes in temperature, the presently knownsunlamps often or invariably employ blowers or other suitable coolingmeans. Such cooling means can be omitted if the radiation sources 3 arelow-pressure mercury lamps containing a chemical additive (e.g.,amalgam) which is capable of insuring a constant UVA radiation outputand a constant relative spectrum independently of temperature changes.

The density of the field 13 in front of the window 2 is enhanced byplacing the radiation sources 3 close to each other. As a rule, thedistance b between two neighboring sources 3 should not exceed (and ispreferably less than) the diameter c of a source.

FIG. 2 shows one of the rod-like low-pressure mercury lamps 3 and theassociated trough-shaped reflector 4. The reflector 4 comprises two sidewalls 4A with substantially parallel front portions 14 and rear portions19 having concave inner surfaces facing each other, a rear wall 4Bhaving two portions 17 which are mirror symmetrical to each other withreference to the plane 12 and include concave front surfaces facing therear side of the source 3, and two relatively narrow intermediate walls18 having concave inner surfaces which merge into the inner surfaces ofthe respective rear portions 19 as well as into the inner surfaces ofthe respective portions 17 of the rear wall 4B. The center of curvatureof the front surface of the left-hand portion 17 of the rear wall 4B isshown at 17a, the center of curvature of the inner surface of theleft-hand intermediate wall 18 is shown at 18a, and the center ofcurvature of the inner surface of the left-hand rear portion 19 is shownat 19a. The radii of curvature of the front surfaces of portions 17 maybut need not equal the radii of curvature of the inner surfaces of rearportions 19, and each such radius is several times the radius ofcurvature of the inner surface of the left-hand or right-handintermediate wall 18. The reflector 4 has two identical halves which aremirror symmetrical to each other with reference to the plane 12, i.e.,to a plane which includes the axis of the source 3 and halves the rearwall 4B. The exit opening for radiation is shown at 2'; this openingextends between the foremost parts of front portions 14 of the sidewalls 4A, and such front portions preferably extend at least slightlybeyond the foremost part of the source 3 so that the entire source 3 isfully received in the space between the side walls 4A and rear wall 4B.The side walls 4A define with the source 3 two relatively narrow gaps orclearances 16 for the passage of rays toward the exit opening 2'. Theinner surfaces of the front portions 14 of side walls 4A may butpreferably do not diverge from each other in a direction toward the exitopening 2'. Rays 15a which issue from the front part of the source 3 andimpinge upon the inner surfaces of the front portions 14 are reflectedinto the exit opening 2', i.e., toward the field 13 of FIG. 1. Theaforediscussed configuration of the rear portions 19 of the side walls4A, of the rear wall 4B and of the intermediate walls 18 insures that avery high (normally by far the major) percentage of rays issuing fromthe rear side of the source 3 is reflected into the gaps 16 and thenceinto the exit opening 2'. As shown in FIG. 2, a ray 15 b which impingesupon the left-hand portion 17 of the rear wall 4B can be reflecteddirectly into the left-hand gap 16. A ray 15c which issues from the rearportion of the source 3 and impinges upon the left-hand rear portion 19is reflected against the right-hand intermediate wall 18 which reflectsthe ray 15c into the right-hand gap 16. The rear portions 19 of the sidewalls 4A may merge gradually into the respective front portions 14 or(see FIG. 2) the side walls 4A may be formed with pronounced internalridges which are adjacent to narrowest portions of the respective gapsand constitute the loci where the foremost parts of the rear portions 19meet the rearmost parts of the respective front portions.

The aforedescribed configuration of the walls 4A, 18, 18 and 4Bcontributes to the density of the radiation field 13 because the concavesurfaces of these walls are capable of directing into the gaps 16, andthence into the exit opening 2', all or nearly all rays which issue fromthe rear side of the source 3, i.e., from that side which is locatedrearwardly or inwardly of the narrowest portions of the gaps 16.

In the coordinate system of FIG. 3, the wavelength lambda of ultravioletradiation issuing from the source 3 is measured along the abscissa andthe relative sensitivity Z_(rel) of human skin to ultraviolet radiationof different wavelengths is measured along the ordinate. The wavelengthis measured in nm (nanometers). The ultraviolet radiation range isbetween 200 and 400 nm. The band between 200 and 280 nm (theaforementioned UVC band) is followed by the socalled UVB band between280 and 315 nm, and the UVB band is followed by the UVA band between 315and 400 nm.

The solid-line curve I of FIG. 3 shows the variations of tanning effectof ultraviolet radiation upon the human skin as a function ofwavelength. It will be noted that the tanning effect is produced byradiation in the band UVA and in the right-hand portion of the band UVB(between 300 and 400 nm), and that such effect is most pronounced at 340nm. The phantom-line curve II of FIG. 3 is representative of relativesensitivity of human skin to sunburn as a function of wavelength. Thesensitivity curve II has a peak (at 297 nm) in the UVB band and ends inthe UVA band (at 320 nm). The sensitivity of human skin to sunburn inthe band UVA is practically nil. In accordance with a feature of theinvention, ultraviolet radiation in the bands UVC and UVB is intercepted(either entirely or to a very high degree) by the tubular envelope ofthe source 3 and/or by a filter (e.g., the pane 9 of FIG. 1) which isinstalled between the exit openings 2' of the reflectors 4 and the field13 of FIG. 1. This insures that the field 13 consists practicallyexclusively of radiation in the UVA band, i.e., in a band which does notcause any sunburn but is most effective for rapid tanning of human skin.Therefore, the person using the improved apparatus can receive highdosages of radiation during a long and uninterrupted interval of time toinsure pronounced tanning without any danger of sunburn. In order toproduce a tanning effect, the radiation must exceed a threshold value of7.5 to 10 w/cm² ; such threshold values can be reached and exceededwithin a relatively short interval of continuous exposure to radiationin the field 13.

In the coordinate system of FIG. 4, the wavelength (lambda) of radiationis measured along the abscissa (in nm) and the relative distributionV_(rel) of radiation density is measured along the ordinate. Thesolid-line curve III represents the density of radiation furnished by alow-pressure mercury lamp at different wavelengths. The low-pressurelamp is assumed to have been subjected to special treatment to increasethe output of radiation in the UVA band (315-400 nm). It will be notedthat the curve III has a pronounced peak in the UVA band. Thebroken-line curve IV represents similar characteristics of ahigh-pressure mercury lamp which was subjected to special treatment toincrease the output in the range of ultraviolet light. The phantom-likecurve V represents similar characteristics of a Xenon lamp. It will beseen that the output of a low-pressure mercury lamp is most satisfactoryin the UVA band of ultraviolet light; this is in contrast to the outputof a high-pressure mercury lamp or a Xenon lamp. However, the output ofa high-pressure mercury lamp or a Xenon lamp can greatly exceed theoutput of a low-pressure mercury lamp which, in turn, enables thehigh-pressure mercury lamps and Xenon lamps to supply large quantitiesof ultraviolet radiation in spite of the fact that they are moreeffective in the range of visible and/or infrared light.

FIG. 5 shows an apparatus 23 which is a table model and includes ahollow spherical housing 24 mounted on a suitable pedestal 31,preferably in such a way that the user can change the angular positionand/or the inclination of an exit opening 2A. The exit opening 2Areceives a plate-like filter 25 for UVB and UVC bands of ultravioletradiation. The material of the filter 25 is assumed to be such that itintercepts all or nearly all radiation having a wavelength between 200and 315 nm.

The housing 24 contains a horizontal rod-shaped high-pressure mercurylamp 26 located between the exit opening 2A and the rear wall 28 of areflector 27. The length of the source 26 is 20 centimeters, and itsoutput is assumed to be in the range of 1,000 to 2,000 watts. It isfurther assumed that the source 26 has been subjected to a specialtreatment to increase the radiation output in the UVA band. The part 26can be said to constitute a substantially point-shaped source ofultraviolet radiation.

The reflector 27 is a substantially bowl-shaped wide-angle reflectorwhose rear wall 28 is closely adjacent to the rear side of the source 26and whose divergent side walls extend all the way to the exit opening2A. The configuration of the rear wall 28 of the reflector 27 issomewhat similar to that of the rear wall 4B shown in FIG. 2. Ahigh-density radiation field 13A develops at a distance d from the exitopening 2A. The development of such high-density field is attributable,at least to a substantial extent, to the fact that the rear wall 28 ofthe reflector 27 reflects all or nearly all rays which issue from therear portion of the source 26 and directs such rays toward the exitopening 2A.

The housing 24 further contains customary auxiliary equipment 29 (e.g.,timer means, chokes, etc.) and the controls 30.

The high-pressure mercury lamp 26 can be replaced with a Xenon lamp andthe filter 25 may constitute (or may be combined with) a plate whichintercepts heat but permits the UVA band of ultraviolet radiation toreach the area of the field 13A. Alternatively, the reflector 27 may beof a type which reflects ultraviolet radiation but permits passage of atleast some light and heat which latter is then withdrawn from the spacebehind the reflector (for example, in a manner as shown in FIG. 17). Theprovision of such reflectors is desirable if the radiation sourcesconstitute high-pressure mercury lamps or Xenon lamps which producesubstantial amounts of light and/or heat energy (see FIG. 4).

Still further, the apparatus of FIG. 5 can be modified by using areflector which reflects only ultraviolet light and is disposed at anangle of 20 to 50 degrees to incident radiation. The reflector reflectsultraviolet radiation laterally toward the area when the high-densityfield is readily accessible to a person and permits at least a very highpercentage of light and heat to pass therethrough. It has been foundthat such apparatus are a more effective means for preventing exposureof a person to excessive amounts of heat energy than those apparatuswherein the heat absorbing or intercepting means is installed in theexit opening. Another advantage of the apparatus of FIG. 5 is that theeyes of a person standing or sitting in the region of the high-densityradiation field are shielded from bright light.

The source 26 of FIG. 5 is preferably a lamp with an UVA radiationoutput of at least 20 watts, and the angle of divergence of the frontportions of side walls of the reflector 27 is preferably at least 80degrees, most preferably at least 100 degrees. Such wide-angle reflectoris capable of insuring uniform distribution of reflected ultravioletradiation as well as the development of a relatively large high-densityfield 13A close to the exit opening 2A. The overall radiation output ofa high-pressure mercury lamp or Xenon lamp which can furnish at least 20watts in the UVA band of ultraviolet radiation is normally between 1,000and 2,000 watts. The apparatus of FIG. 5 can be designed to insuresimultaneous tanning of the face, shoulders and the upper part of thetorso of a person sitting or standing in front of the exit opening 2A.

The apparatus 32 of FIG. 6 can be mounted on the ceiling or on a wall ofa room and comprises three discrete sunlamps or units 23 which may butneed not be identical with the apparatus 23 of FIG. 5. Each unit 23comprises a hollow spherical housing 24 with an exit opening 2A facing acot, bed, bunk or couch 34 therebelow. The housings 24 are suspended ona horizontal carrier 33 which is attached to the adjacent ends of cords,cables or analogous flexible elements 36. The flexible elements 36 aretrained over pulleys 37 and their other ends are connected to acounterweight 38 or a winch (not shown) which enables a person to changethe distance between the housings 24 and the bed 34 with a minimum ofeffort or by starting a reversible motor for the winch.

The distances between neighboring housings 24 are selected in such a waythat the outermost rays 35 issuing from the radiation sources (notshown) of the respective units 23 cross each other at a distance f=10-30centimeters from the exit openings 2A. This is the region where thedensity of the radiation field 13A' is most satisfactory for a personoccupying the bed 34.

The units 23 are lifted to afford convenient access to a patient whowishes to occupy the bed 34, to enable the patient to leave the bed 34,and/or to change the level of the radiation field 13A' during orpreparatory to treatment.

It has been found that three units of the type shown in FIG. 5 normallysuffice to develop a field 13A' which is large enough to allow forsimultaneous tanning of the entire body. It is clear that the units 23of FIG. 6 can be mounted one above the other so that a person can standin front of the apparatus. Also, the carrier 33 of FIG. 6 can be mountedin such a way that it is movable between the illustrated horizontalposition for treatment of a person on the bed 34 or to a verticalposition in which the units 23 are located one above the other to enablea standing patient to take a sunbath.

The UVA radiation output of a rod-shaped Xenon lamp is normally at least50 watts per meter. Such lamps can be used in the apparatus of FIGS. 5or 6. Each Xenon lamp is associated with a discrete reflector (e.g., areflector 27) and its overall output normally exceeds 1,000 watts. Theoverall output of a Xenon lamp having a length of 40 centimeters isnormally between 1,500 and 2,000 watts, and the overall output of aXenon lamp having a length of 150 centimeters is normally in the rangeof 9,000 watts.

The radiation-intercepting action of the plate-like filter 25 of FIG. 5(and of the corresponding filters in the units 23 of FIG. 6) can betaken over by the tubular envelopes of the respective radiation sources.The filter or filters 25 can be mounted in such a way that they can bemoved into and away from the respective exit openings, for example, inorder to allow for short-lasting exposure of skin to radiation in theentire range of ultraviolet light.

The bed 34 insures that a patient whose body is resting thereoninvariably assumes an optimum position with respect to the units 23,i.e., with respect to the high-density radiation field 13A'. Thisenhances the effectiveness of the apparatus because the patient iscompelled to maintain his or her body at an optimum distance from theexit openings 2A. The same effect can be achieved if the units 23 aremounted one above the other, for example, by providing an uprightpartition in front of which the patient stands while his or her skin isexposed to ultraviolet radiation in the range of 315 to 400 nm.

The apparatus 39 of FIG. 7 resembles a kiosk or tower and includes asubstantially semicylindrical housing 41 mounted on a round base plate40 and having a roof 42. The front side of the housing 41 can be closedby a glass door 47 which is mounted on hinges 49 and has a knob 48. Thecontrols 44 (FIG. 8) include one or more actuating knobs 43 which aremounted at the front side of the housing 41 adjacent the knob 48. Theapparatus 39 is assumed to be used in a public or private bath, in agymnasium, clinic, hospital or a similar institution and has one or moreslots 45 for insertion of coins which actuate a coin-operated starter 46shown in FIG. 8. The housing 41 further contains the customary auxiliaryequipment 53.

The space behind the door 47 contains three roof-shaped wide-anglereflectors 52 for three aligned upright rod-shaped radiation sources 51(e.g., Xenon lamps). The door 47 constitutes a filter for the UVB andUVC bands of ultraviolet radiation. For example, each source 51 may havea length of 60 centimeters and an output of 4,000 watts. The arrangementis such that a high-density radiation field develops at a distance ofapproximately 20 centimeters from the front side of the door 47. Inorder to enable the user to assume an optimum position with respect tothe sources 51, the base plate 40 is formed with indicia 50 in the formof foot prints. The width of the aforementioned radiation field may beapproximately 70 centimeters and the height of the field may beapproximately 180 centimeters. This enables a person standing on theindicia 50 to expose the entire front or rear side of his or her body toultraviolet radiation.

The housing 41 preferably further contains a blower 54 or anothersuitable cooling device which withdraws heat from the space between thedoor 47 and the fixedly mounted heat shields or panes 55 in front of thereflectors 52. The shields 55 can be omitted if the blower 54 is capableof removing sufficient quantities of heat to insure that the temperaturein the region where a person stands (on the indicia 50) is within arange which is below the range of discomfort to the person. As a rule,heat shields and/or one or more blowers will be needed if the sources 51are Xenon lamps because such sources generate substantial quantities ofheat energy.

If the patient wishes to expose (preferably for a short interval oftime) his or her body to ultraviolet rays in the entire range between200 and 400 nm, the door 47 is simply opened before the patient steps onthe indicia 50. The blower 54 is then less effective but the fixedlymounted shields 55 continue to intercept substantial amounts of heatenergy. The door 47 can be replaced with a suitably inclined mirrorwhich is designed to reflect ultraviolet rays in the UVA band in adesired direction but does not reflect heat.

Short-lasting opening of the door 47 might be desirable to build vitaminD, to immunize the patient against certain illnesses, to raise theamount of precursors of melanin, to promote the circulation of bloodand/or to produce other beneficial effects. The controls of theapparatus of FIG. 7 can be designed in such a way that the door 47 isautomatically opened for a preselected interval of time in response toinsertion of one or more coins into the slot or slots 45, especially ifthe door 47 is mounted in such a way that can open or close while thepatient stands on the base plate 40.

FIG. 9 shows a further apparatus having a housing 1B with a window orexit opening 2B in front of upright parallel rod-shaped radiationsources 3B. The starter knob is shown at 8B. The rear portion 56 of theapparatus constitutes a framed mirror, a shelf or another piece offurniture which is attached to the rear side of the housing 1B and ismounted therewith on a common pedestal 57 in such a way that the housing1B and the piece of furniture 56 can be rotated (at least through 180degrees) about a vertical axis. When the apparatus is not in use (fortanning), the piece of furniture 56 is moved in front to afford accessto the contents of the shelf and/or to permit the use of the mirror. Thesources 3B are assumed to constitute low-pressure mercury lamps.

The apparatus of FIG. 10 can be used simultaneously by several personsand can be termed a "tanning bar". This apparatus includes four units ofthe type shown in FIG. 1 and a veranda- or portico-like structure whichconfines the four housings 1D and has a floor 60, two side walls 58 anda roof 59. The stools 61 on the floor 60 can be occupied by personsdesirous of acquiring a tan. Each of the stools 61 can be placed infront of a discrete window or exit opening 2D and can be shifted to aposition in which a selected part of the body is located in themaximum-density radiation field of the respective unit. If desired, thestools 61 can be fixed to the floor 60 in optimum positions with respectto the radiation fields which are produced by the respective units.

FIGS. 11 and 12 show an apparatus 62 which is somewhat similar to theapparatus of FIG. 7; however, it comprises four units each having ahousing 1E and each installed in a separate cell or cabin 63 adapted tobe closed by an arcuate door 64. The pivotable doors 64 can be replacedby curtains or folding doors. The apparatus comprises a base plate 65and a roof 66. Each cabin 63 is flanked by two units having housings 1Eso that a person occupying a selected cabin is exposed to ultravioletradiation from two sides. Two neighboring housings 1E are disposedback-to-back and the housings 1E flanking a cabin 63 make an angle of 90degrees.

It is clear that the apparatus of FIGS. 11 and 12 can be modified byreducing the number of cabins to three or two, or by increasing thenumber of cabins to five or more.

FIG. 13 shows a further apparatus 67 which has several housings 1Fmounted on the floor, side-by-side, and having windows or exit openings2F which are slightly inclined with respect to a horizontal plane. Thewindows 2F contain panes 9F which may constitute filters for the UVB andUVC bands of ultraviolet radiation and which are preferably sturdyenough to support the body of a person lying or sitting thereon. Theapparatus 67 can be assembled of several discrete units, or the housings1F may be made integral with each other. Also, the apparatus 67 may beprovided with wheels or the like to facilitate transport to differentlocales of use or to storage.

The apparatus of FIG. 13 automatically insures that the person restingon one of the filters 9F is located at an optimum distance from theradiation source or sources. In such apparatus, the plane of themaximum-density radiation field preferably coincides with or is veryclosely adjacent to the plane of the respective filter.

Referring to FIG. 14, there is shown an apparatus which is mounted on awall W above a bed or bunk 69. The housing is shown at 1G and its windowor exit opening at 2G. The window faces downwardly and is slightlyinclined with respect to a horizontal plane. The housing 1G is mountedon a frame 69 which is permanently or separatly secured to the wall W.The illustrated inclination of the window 2G is advantageous because theuser has ample room to lie down on or to rise from the bed 69. Thelength of rod-shaped radiation sources (not shown) in the housing 1G ispreferably sufficient (e.g., 150 to 180 centimeters) to allow forsimultaneous exposure of the entire body to ultraviolet radiation in theUVA band.

The apparatus of FIG. 15 comprises a lower unit A and an upper unit B.Each of these units has a sheet metal housing 1H which contains severalradiation sources 3H each having a length of 180 centimeters. Theassociated reflectors are shown at 4H.

The lower unit A is mounted on a support 70 and can be said to form partof a cot, bed, couch or bunk on which a person can rest during exposureof his or her skin to ultraviolet radiation. The ends of the upper unitB are secured to a wall W by semicircular brackets 71 having plates 72for a pivot 73 which carries the upper housing 1H. The upper housing 1His pivotable about the horizontal axis of the member 73 so as to changethe inclination of exit openings on windows 2H and panes or filters 9Hwith respect to the lower unit A. Means (not shown) is provided toreleasably hold the upper unit B in a selected angular position. Theillustrated angular position (in which the windows 2H of the upper unitB are located in a horizontal plane) has been found to be an optimumposition. The distance a' between the planes of the upper and lowerwindows 2H may be in the range of 40 to 60 centimeters. This normallysuffices to enable a person to lie down on the unit A and have his orher body exposed to radiation issuing from the units A and B. It isclear, however, that the apparatus of FIG. 15 may comprise controlswhich enable the user to turn on the unit B independently of the unit Aor vice versa.

The apparatus of FIG. 15 may comprise a third unit which can be mountedon the wall W so that a person resting on the unit A is exposed toultraviolet radiation from below, from above, as well as from one side.The third unit may but need not be identical with the unit A or B.

The apparatus 74 of FIG. 16 resembles a horizontal barrel which ismounted on legs 75. The interior of the apparatus comprises a lower unitA' which may be analogous to or identical with the unit A of FIG. 15,and an upper unit B' which forms part of the upper portion of theapparatus. The apparatus further includes two additional (lateral) unitsC. Each unit comprises several parallel rod-shaped radiation sourcesassociated with reflectors and mounted behind elongated strip-shapedfilters 76 made of glass or other material which intercepts certainbands of ultraviolet radiation. The filters 76 of the units C and B'together form an internal liner of the barrel and the liner extendsalong an arc of at least 180 degrees. The liner may form part of acircular cylinder, a cylinder having an oval shape or a cylinder whichhas a more or less pronounced polygonal cross-sectional outline. In eachinstance, the body of a person occupying the unit A' is exposed toultraviolet radiation from all sides. The exit openings of thereflectors in the units A', B' and C are shown at 2K.

Referring finally to FIG. 17, there is shown an apparatus 101 whichcomprises a rod-shaped radiation source 102, a trough-shaped reflector103, an auxiliary reflector 104 in front of the source 102, asubstantially cylindrical housing 107 with an exit opening 106, and aplate-like filter 105 in the opening 106.

The reflector 103 consists of two halves which are mirror symmetrical toeach other with respect to a plane including the axis of the source 102and extending at right angles to the plane of the filter 105. Thecentral portion of the rear wall of the reflector 103 has a pronouncednotch 108 which is closely adjacent the rear side of the source 102. Therear wall and the rear portions of the side walls of the reflector 103constitute mirrors or are coated with reflecting material forultraviolet radiation (indicated by a heavy line 109), and the frontportions of the side walls of the reflector diverge toward the exitopening 106. Each of the two halves of the reflector 103 has a concaveinner surface which begins at the respective side of the exit opening106 and ends at the notch 108. The space 111 between the rear side ofthe reflector 103 and the housing 107 constitutes a cooling zone whereinair is circulated by one or more blowers 112 or the like.

It is assumed that the source 102 of FIG. 17 is a Xenon lamp. Asindicated by the curve V of FIG. 4, such lamp emits ultravioletradiation mainly in the UVA band (between 315 and 400 nm). FIG. 4further shows that the lamp 102 emits substantial amounts of radiationin the range of visible and infrared light. Therefore, the mirroredportion 109 of the reflector 103 of FIG. 17 is designed to reflectprimarily ultraviolet radiation (see the ray 113) but to permit passageof heat (see the ray 114) so that heat energy can be withdrawn from thezone 111 by turning on the blower 112. Light which passes through thereflector portion 109 is reflected by the housing 107 and is alsoconverted into heat energy which is withdrawn by the blower 112. Thefilter 105 intercepts the bands UVA and MVC so that only the band UVA(see the ray 115) advances beyond the window 106 and reaches the skin ofa person who is located in front of the housing 107. The portion 109 ofthe reflector 103 reflects these rays (shown at 116) which issue fromthe rear side of the source 102 and directs such rays toward the exitopening 106. Each ray 116 can be reflected once or more than once. Theauxiliary reflector 104 intercepts light and heat radiation which wouldbe annoying to a person facing the window 106. Furthermore, thereflector 104 insures that all rays which are not immediately directedtoward the reflector 103 are reflected onto the portion 109 whichpermits the light and heat rays to pass and reflects only ultravioletrays. The reflector 104 thus insures that radiation issuing from thefront half of the source 102 cannot propagate itself directly toward thewindow 106 but is reflected toward the main reflector 103 which reflectsonly ultraviolet radiation whereby the ultraviolet rays travel towardthe filter 105 which permits the band UVA to reach the patient. Thedensity of the relatively large radiation field which develops in frontof the exit opening 106 is very pronounced, and such field consistsexclusively or almost exclusively of UVA radiation. Thus, the percentageof light rays, infrared rays and ultraviolet rays in the UVB and UVCbands is negligible.

The improved apparatus is susceptible of many additional modificationswithout departing from the spirit of the invention. For example, theapparatus shown in FIGS. 8 to 15 can utilize radiation sources in theform of high-pressure mercury lamps (FIGS. 5 and 6) or Xenon lamps(FIGS. 7 and 8). Furthermore, the apparatus or one or more of its unitscan be installed in the niche or niches of a wall. Still further, theapparatus may be installed in the corner of a room and its door or doorsmay constitute one or more mirrors which can be used when the doors areclosed. Also, the controls of the apparatus may be programmed so thatthe apparatus is turned on, operated for a selected period of time, andturned off in automatic response to actuation of a single knob or thelike. The programming may be such that the filter or filters for the UVBand UVC bands can be moved away for a given period of time at the startof a treatment and are thereupon returned to operative positions in afully automatic way. Moreover, the tubular envelopes of the radiationsources can constitute filters which replace the platelike filter 105 ofFIG. 15 and the corresponding filters in other embodiments of theapparatus.

It is further clear that the improved apparatus can be used for otherpurposes, i.e., not only for artificial tanning of human skin. Forexample, the high-density field which consists (exclusively or nearlyexclusively) of ultraviolet radiation in the UVA band can be used fortherapeutical purposes and/or to produce other beneficial effects.

Extensive experimentation with the improved apparatus indicates that thehigh-density field or fields are preferably located at a distance of 0to 30 centimeters from the exit opening or openings, most preferably ata distance between 10 and 20 centimeters. The density of the radiationfield is at least 4 mw/cm², preferably between 5 and 30 mw/cm² and mostpreferably about 15 mw/cm². In a table model, the area of the field isin the range of 0.2 m². In a solarium, the area of the field ispreferably at least 0.5 m² (e.g., the field may have a length of atleast 120 centimeters and a width of at least 50 centimeters).

Certain radiation sources which are presently available on the marketand can be used in the apparatus of the present invention includelow-pressure mercury lamps of the type TL/05 or TL/09 produced byPhilips, high-pressure mercury lamps of the type PQ produced bySueddeutsche Metallwerke of Federal Republic Germany, and Xenon lamps ofthe type XOP 25 produced by Philips.

As mentioned above, the tanning effect upon human skin is producedprimarily by ultraviolet radiation in the UVA band between 315 and 400nm. Furthermore, the tanning begins when the amount of radiation withinthe range of 315 to 400 nm reaches or exceeds a predetermined(relatively high) threshold value. Such threshold value depends on thenature of skin and is normally between 7.5 and 10 mw per squarecentimeter. The improved apparatus insures that the threshold value isexceeded within a relatively short interval of time by rendering itpossible that a person can stand, sit or lie close to the exit openingor openings, i.e., at a distance which is only a small fraction of thedistance prescribed in connection with conventional sunlamps. In fact,and as pointed out above, a person can be positioned immediatelyadjacent the exit opening or openings. This insures that the density ofthe radiation field in which the human skin is located is very high. Atthe same time, the filter means of the radiation source or sourcesand/or discrete filter means in, in front of, or behind the exit openingor openings protect the skin from sunburn by preventing radiation in the200 to 315 nm range from reaching the skin. In conventional sunlamps,the likelihood of sunburn increases if the person moves nearer to theexit opening. The amount of heat energy which reaches the skin duringtreatment can be kept within a range which is below the range ofdiscomfort to the person using the apparatus by resorting to low-outputradiation sources and/or by resorting to heat absorbing means of anysuitable design. This enables the person using the apparatus to remainclose to the exit opening or openings for extended periods of time, notonly because the person is protected from sunburn but also because theintensity of heat is sufficiently low to enable such person to stand thetreatment for as long as necessary, e.g., to acquire a pronounced tan inthe course of a single treatment.

Since the area of the high-density radiation field decreases if thefield is produced close to the exit opening or openings, the improvedapparatus can use two or more radiation sources and an equal number ofreflectors to establish a field having an area which suffices to exposethe selected portion or portions of or the entire body of a person tothe UVA band of ultraviolet radiation, also in such a way (see, forexample, FIG. 12, 15 or 16) that the body is exposed to radiation comingfrom two or more sides. The just mentioned advantageous feature of theapparatus can be achieved by appropriate selection of the number,orientation, distribution and dimensions of the radiation sources and/orassociated reflectors.

Experiments with the improved apparatus indicate that a pronouncedtanning effect, at a density of 4 mw per square centimeter, can beachieved by continuous exposure of skin to UVA radiation for a period of30 minutes. The period of treatment can be reduced by increasing thedensity of the field to 5-30 mw per square centimeter. If the density isreduced below 4 mw/cm² (e.g., to 2 mw/cm²), the treatment (which can bebroken up into two or more sessions) takes longer (e.g., one hour). Thejust mentioned periods can be shortened by reducing the threshold valueof tanning effect of UVA radiation by suitable sensitizing means.

The breaking up of treatment into two or more sessions is optionalbecause a continuous treatment is neither uncomfortable nor dangerous tothe patient or patients. For example, a person who wishes to acquire apronounced tan and can afford to spend a relatively long period of timein front of, above or below one or more radiation sources can resort toa single session. On the other hand, a person who does not wish toacquire a pronounced tan in a single day will break up the treatmentinto two or more sessions. The improved apparatus can be set up inpublic areas, such as baths, hotels, motels, guesthouses, airlineterminals, recreation rooms of hospitals or schools, assembly rooms ofcommunity centers and many others. As a rule, a person who desires toacquire a pronounced tan will prefer to achieve his or her objective ina single session or in a small number of (e.g., two or three) sessions.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic and specific aspects of my contributionto the art and, therefore, such adaptations should and are intended tobe comprehended within the meaning and range of equivalence of theappended claims.

What is claimed is:
 1. Apparatus for producing ultraviolet radiation andconstituting or forming part of a quick-tanning sunlamp, comprising anirradiating unit including at least one source of ultraviolet radiation,means associated with said source and defining at least onesubstantially horizontal exit opening for ultraviolet radiation, saidopening being disposed below said source, said source and saidassociated means being constructed and assembled to establish ahigh-density radiation field of predetermined area at a small distancefrom and below said exit opening, and means for intercepting at leastthe major percentage of wavelength bands of ultraviolet radiation belowapproximately 315 nm ahead of said field as considered in the directionof propagation of the radiation toward said field; and means formounting said unit for substantially vertical movement toward and awayfrom the body of a user of the apparatus to thereby adjust the positionof said field relative to the body.
 2. Apparatus as defined in claim 1,wherein said source comprises at least five closely adjacent rod-shapedlow-pressure mercury lamps.
 3. Apparatus as defined in claim 1, whereinsaid associated means comprises reflector means for said source ofultraviolet radiation.
 4. Apparatus as defined in claim 3, wherein saidsource comprises a plurality of closely adjacent substantially parallelrod-shaped lamps which are separated from each other by gaps and saidreflector means includes a discrete reflector for each of said lamps,said reflectors having side walls disposed in the gaps betweenneighboring lamps.
 5. Apparatus as defined in claim 1, wherein saidsource includes a plurality of closely adjacent elongated lamps and saidassociated means includes a discrete reflector for each of said lamps,each of said reflectors surrounding the respective lamp along an arc ofat least 180 degrees.
 6. Apparatus as defined in claim 5, wherein saidreflectors have substantially parallel side walls which projectforwardly beyond said lamps.
 7. Apparatus as defined in claim 1, whereinsaid source includes a plurality of elongated rod-shaped lamps, saidlamps being closely adjacent to each other and the distance betweenneighboring lamps being at most equal to the diameter of a lamp. 8.Apparatus as defined in claim 1, wherein said source includes aplurality of elongated lamps having tubular envelopes which constitutesaid intercepting means.
 9. Apparatus as defined in claim 1, furthercomprising a bed to support the body of the user, said exit openingfacing downwardly toward said bed.
 10. Apparatus as defined in claim 9,further comprising means for moving said unit up and down away from andtoward said bed.
 11. Apparatus as defined in claim 10, wherein saidmeans for moving said unit comprises a reversible motor.
 12. Apparatusas defined in claim 1, wherein said source is a source of substantiallyuniform ultraviolet radiation and includes at least five closelyadjacent rod-shaped low pressure mercury lamps, said associated meansincluding reflector means having a discrete trough-shaped reflector foreach of said lamps, each of said reflectors surrounding the respectivelamp along an arc of at least 180 degrees and the heat output of saidlamps being sufficiently low to insure that the temperature in theregion of said field is within a range which is below the range ofdiscomfort to a person exposed to said field.
 13. Apparatus as definedin claim 1, wherein said source consists of a plurality of lamps and theoutput of said lamps in the bands above 315 nm is at least 5 watts permeter.
 14. Apparatus as defined in claim 1, wherein said sourcecomprises between five and twenty lamps.
 15. Apparatus as defined inclaim 12, wherein the number of said lamps is between ten and twelve.16. Apparatus as defined in claim 1, wherein said source comprises aplurality of lamps and the output of each of said lamps in the bandsabove 315 nm is at least 8 watts per meter.
 17. Apparatus as defined inclaim 1, wherein said source comprises a plurality of elongated lampseach having a length in excess of 100 centimeters.
 18. Apparatus asdefined in claim 15, wherein the length of each of said lamps isapproximately 150 centimeters.
 19. Apparatus as defined in claim 15,wherein the length of each of said lamps is approximately 180centimeters.
 20. Apparatus as defined in claim 1, wherein saidintercepting means is located in said exit opening.
 21. Apparatus forproducing ultraviolet radiation, particularly a quick-tanning sunlamp,comprising at least one source of ultraviolet radiation; meansassociated with said source and defining at least one exit opening forultraviolet radiation, said source and said associated means beingconstructed and assembled to establish a high-density radiation field ofpredetermined area at said exit opening; and means for intercepting atleast the major percentage of wavelength bands of ultraviolet radiationbelow approximately 315 nm ahead of said field, as considered in thedirection of propagation of the radiation toward said field, includingat least one mirror reflecting radiation of wavelengths upwardly ofapproximately 315 nm from said source toward said field, and permeatedby radiation of wavelengths below approximately 315 nm for travel in apath remote from said field.